Intracranial hematoma from a slow venous bleed comprises a major cause of late death and disability in head trauma patients who initially appear asymptomatic. Hematoma detection is currently done by a CAT or MR scan, which is a costly and, in many hospitals, an inaccessible diagnostic modality. A need exists in clinical practice for a device to detect intracranial bleeding, that is less expensive and more widely available than CAT or MR imaging. This proposal is to develop a novel low- frequency, low PRF pulse Doppler ultrasound instrument to detect brain displacement overtime (brain velocimeter). Based on feasibility studies, the device will measure, in ten minutes, brain velocity at a series of positions between the temporal bones, the venue associated with 80% of intracranial hematomas. In Phase I, the best carrier frequency will be determined and a prototype velocimeter will be built and tested on a phantom model of intracranial hemorrhage, as well as a series of patients presenting with head trauma and referred for diagnostic CAT imaging. Phase II will include instrument redesign based on Phase I results and multi-center clinical trials. Phase II results will be used to design a Phase III device for the commercial market. PROPOSED COMMERCIAL APPLICATIONS: The instrument to be developed in this project, a brain velocimeter, will perform fast detection of very slow brain movement due to intracranial bleeding associated with head trauma. The instrument will not require an expert user and will target nurse and physician staff in the emergency medicine market. This simple to use low-tech ultrasound device will be aimed at a world wide market, especially where the current gold standard, CAT or MR imaging, is not affordable.